The field of the invention is fuel dispensing and containment systems and the invention relates more particularly to systems which utilize a fuel tank which is held in an underground concrete vault. The vast majority of “gas stations” utilize fuel storage tanks which are buried directly underground. Years ago, there was a lack of appreciation of the negative consequences of fuel leaking from the underground tank and associated piping into the ground. With the present enlightened ecological sensitivity, vast amounts of money are spent to try to remove all fuel which might have leaked from such storage tanks and piping into the surrounding ground water table. Various funds have been established to help finance such cleanup procedures and a per-gallon charge is levied against dispensed fuel to create the necessary funds for cleanup. If the fuel is stored in a tank above ground, such surcharge is not levied, since there is essentially no possibility of fuel passing from the tank or its attendant piping to an underground location.
Various vaults containing tanks have been designed. One such system is shown in U.S. Pat. No. 4,978,249, where two tanks are shown in a segmented vault which has a top mounted at ground level. A pipe chase abuts one side of the tank and also has a top at ground level.
U.S. Pat. No. 5,244,307 shows a fuel dispensing system where the fuel storage tank is positioned directly under the dispensers. The piping is located above grade level.
An above-grade storage vault is shown in U.S. Pat. No. 5,582,310 where a steel storage tank is maintained within a concrete vault.
U.S. Pat. No. 5,769,109 utilizes a concrete vault to provide overflow containment in the event of any fuel leak.
U.S. Pat. No. 6,196,761 shows an underground storage vault also located directly under the dispensers. Also, only one end of the tank is available for visual inspection.